Molecular Scale Structure and Kinetics of Layer-by-Layer Peptide Self-Organization at Atomically Flat Solid Surfaces.

Area of Science:

• Biomolecular self-assembly
• Surface science
• Nanotechnology

Background:

• Understanding peptide self-organization is crucial for biomolecular systems.
• Studying dynamic assembly processes at the submolecular level is challenging.
• Peptide self-organization on surfaces offers a promising approach to overcome these challenges.

Purpose of the Study:

• To investigate the in situ self-organization of a specific dodecapeptide (GrBP5) on a graphite surface.
• To elucidate the formation mechanisms of the first two peptide layers.
• To understand the influence of peptide concentration on assembly dynamics and structures.

Main Methods:

• Frequency modulation atomic force microscopy (FM-AFM) was used for in situ observation.
• The study focused on the self-organization of GrBP5 on highly oriented pyrolytic graphite (HOPG).
• Peptide assembly was monitored in an aqueous solution.

Main Results:

• The first peptide layer formed a homogeneous crystalline structure commensurate with the graphite lattice.
• The second layer exhibited heterogeneous growth, initiated by defects in the first layer.
• Assembly dynamics, including nucleation and growth rate, were dependent on peptide concentration (>100 μM).
• Self-assembled peptide crystals formed P1 (singlets) and P2 (doublets) oblique lattices with chiral relationships to the graphite.

Conclusions:

• This research provides detailed insights into the surface self-assembly of short peptides.
• The findings offer quantitative guidance for understanding peptide assembly mechanisms.
• The study contributes to the development of bio/nano hybrid interfaces.